Air conditioning of entrance areas



Sept. 1 8, 1956 Filed July 16, 1951 W. J. CALDWELL AIR CONDITIONING OF ENTRANCE AREAS 2 Sheets-Sheet 1 INVENTOR O WILLIAM J- CALDWELL BY wm wm ATTORNEY Sept. 18, 1956 Filed July 16, 1951 W. J. CALDWELL AIR CONDITIONING OF ENTRANCE AREAS 2 Sheets-Sheet 2 FIE- 1T- INVENT OR WILLIAM J- CALDWELL ATTORNEY United States Patent AIR CONDITIONING 0F ENTRANCE AREAS William J. =Caldwell, Independence, Mo.

Application July 16, 1951, Serial No. 237,046

3 Claims. (Cl. 98-33) This invention relates to air conditioning systems and in particular to the air conditioning of buildings which include entrances, such as the doors of vehicle loading docks adjacent to warehouses, which are continually in use and the exhaust gases from vehicles in which loading docks, as well as the tendency for infiltration at the door areas, gives rise to special problems if efficient air conditioning is to be insured.

As distinct from the conventionally employed low velocity air conditioning systems, the present system is concerned with the pressurized high velocity air control system disclosed in co-pending application, Serial No. 187,258, filed September 28, 1950.

It is an object of the present invention to provide an improved air conditioning system employing pressurized high velocity air which efficiently takes care of tendencies for air infiltration at entrances.

It is another object of the invention to provide an air conditioning system in which the relative proportioning of outside fresh air to circulated return air, in a pressurized high velocity air conditioning system, is automatically brought under control to yield the required air conditioning for varying conditions arising in a conditioned building space due to entrances and the generation of gases within the building from sources, such as the exhaust from automobiles, independent of the pressurized conditioning air.

Yet another object of the invention is to provide a pressurized high velocity air conditioning system which combines a heat generator, pressure blower and air fiow duct assembly in a compact and efficient manner. 1

These and further objects and advantages of the invention residing in an arrangement and combination of parts will be clear from consideration of the following description with reference to the accompanying drawings in which:

Fig. I is a schematic view of a typical layout in accordance with the invention as applied to the air conditioning of warehouses (a central portion of which has been broken away) and an adjacent vehicle loading dock, and

Fig. II is a similar view to Fig. I but showing the entire building structure, with the targeting of the air streams A and A from the air control nozzles to the building entrances.

In the drawings there is illustrated a typical layout according to the invention, as applied to a single story building providing a warehouse 10, with an interior oflice 12, and an adjacent loading clock 14. The warehouse is shown with an exit door 16, and an interior door 18, providing access to the loading dock 14, this being shown with a truck ramp 20 and exit door 22 and the interior office being shown with a door 24 having an air grille 26.

The warehouse has an overhead room structure defining a room space 28 and an adjacent room space 30. Each said room space is in communication with afresh air ventilator roof chamber 32 having fresh air dampers 34, serving the room space 28, and fresh air dampers 36, serving the room space 30.

Patented Sept. 18, 1956 Mounted within the room space 28 there is a pressure vane blower 38, serving the warehouse 10, operatively associated with a heat generator 40 and duct system, indicated generally at 42, the generator having a flue 44.

Mounted in the room space 30 there is a pressure vane blower 46, serving the loading dock 14, operatively associated with a heat generator 48 and duct system, indicated generally at 50, 52 and having an associated air flow control nozzle 56'.

As is fully disclosed in the said co-pending application Serial No. 187,258, entrance conditions, at the exit doors 16 and 22, are controlled by pressurizing the building spaces 10 and 14 and directing high velocity conditioned air streams toward these doors, as indicated by the arrows A and A.

In the warehouse 10, the pressure vane blower 38 operates to draw in a mixture of outside air, through the dampers 34, and return air, through dampers 54, and forces it through the heating tubes of the heat generator 40 and thence through air control nozzles 56 into the warehouse 10.

58 indicates a mixed air thermostat and 60 is a damper control motor. The relative amount of outside air employed to return air is dictated by the thermostat 58. The fresh air dampers 34 are so linked to the control motor 60 that even when there is no demand for outside air by thermostat 58 the fresh air dampers 34 are opened suiticiently to admit the amount of outside air required to pressurize the warehouse 10, the actual amount admitted being dependent upon the leakage characteristics of the building structure.

62 indicates a thermostat located at the warehouse exit door 16 and 64 indicates a master thermostat associated with the heat generator 40 and positioned in the return air stream entering the return air dampers 54. The thermostat 64 functions to control the heat input to the heat generator by controlling the heat generator in conventional manner, whereas the thermostat 62 functions to actuate a damper motor 66 linked to the speed controller of the variable speed fan motor 68 so as to control the motor speed, and hence the operation of the pressure vane blower 38, to insure that the required warehouse pressurization and jet velocity (from the nozzles 56 are maintained to meet the prevailing demand. Thus were cold air to blow through the door 16 into the warehouse, it would strike the thermostat 62 and cause an increase in pressurization and jet velocity until the entering draft was offset. Since the system employed (as disclosed in the said co-pending application) produces uniform temperature diffusion, the return air forms an accurate index of the overall building temperature and can be employed as an actuating medium for the control thermostat 64.

The duct 42 is shown in the form of a duct 70 leading to the nozzles 56 and another duct 72, a part of which traverses part of the heater tubes of the heat generator 40 and which duct 72 leads to a centrifugal nozzle 74in the ceiling of the interior oflice 12. The duct system 70 and 72 is brought under the control of a splitter damper 76 actuated by a motor 78, in turn controlled by a thermostat 80 in the ofiice 12. The arrangement is such that the relative amount of air by-passed into the duct 72 is controlled by the thermostat 80, motor 78 and splitter damper 76, the latter having a damper controlling the amount of air delivered to the heat generator from the pressure vane blower 38.

82 is a low-limit thermostat located in the heater outlet side of the duct 70 and linked to the heater control to prevent cold air being delivered through the nozzles 56 in the event that the main control thermostat 64 fails for any reason, or is satisfied by the return air stream tem p'e'raturc. i

Turning now to the conditioning of the loading dock 14, located at the communication door 18 there is a trip switch 84 having a suitable actuator 84' engaging with the door 18, which is mounted so as to be moved to one position, when the door 18 is fully opened, and to the reverse position, when the door is closed. This switch 84 is connected in circuit with the motor 60 and another motor 86, the motor 60 controlling the fresh air dampers 34 and the motor 86 controlling the return air dampers 54. The connection is such that when the door 22 is opened and switch 84 is tripped, the motor '86 functions to close the return air dampers 54 completely and the fresh air dampers 34 are opened. In this condition, all of the air driven into the warehouse has no other avenue of escape except through the doors 16 and 18, if opened, the pressurized flow of which air to these possible entrances counteracts any inflow tendencies therethrough.

Motor 60 and motor 86 operate concurrently from the dictates of the mixed air thermostat 58, but in opposition to one another, such that the return air dampers 54 close when the fresh air dampers 34 open, and vice versa.

The two motors 60 and 86 are controlled independently of the desires of the thermostat 58, which is removed from the motor control circuit when switch 84 is actuated to the operating position.

Provision is made, with respect to the loading dock 14 to deal with exhaust gases from the vehicles accommodated therein. With the conventional low pressure conditioning systems, the heavy exhaust gases generated by the vehicles settle and may produce dangerous atmosphere concentrations at breathing level by virtue of this stratification. With the high velocity and pressurized system herein employed, however, and disclosed in the said co-pending application, the mixing of the total air mass in a given room space is so complete that this stratification cannot occur since the energy imposed on the mass is a relatively much greater force than that of the different densities of the gas and air otherwise tending to cause stratification. It thus becomes only necessary to introduce an amount of outside air directly proportional to the amount of exhaust gases generated by the vehicles to effect a safe dilution thereof. This is effected through the medium of a motor 88 initially adjusting the fresh air dampers 36 so as to introduce the necessary amount of air at the lowest speed of the blower 46, with the maximum number of vehicles operating in the loading docks with the door 22 closed. This amount of air would certainly be less than that corresponding to the total number of trucks accommodated in the loading dock, based upon the assumption that only those vehicles would be left running which were either just entering -or about to leave the dock and that when the door 22 is closed the vehicle motors would mostly be shut off, as during protracted loading periods.

The motor 88 is shown linked to a thermostat 90, motor 92 controlling the return air dampers 94 to the return air duct 52, and to a trip switch 96 located at the door 22 (there being one such switch for each door, if more than one is present).

The switch 96 having a suitable actuator 96 which is so adapted that when the door 22 is opened the switch is actuated by the door portion 22 to cause the return air dampers 94 to close, through over-operation of motor 92, so that all the pressurized air supplied to the dock 14 is constrained to flow through the open door 22. In this way, if the door 22 is normally closed only a nominal amount of fresh air is supplied. Further if the door 22 is only casually opened, as to quickly accommodate an arriving or leaving vehicle, the time the door is opened would probably be of such short duration that the damper control motors 88 and 92 would be given insufficient time in which to complete their cycle so that the normal fresh air supply would .not be unduly disturbed. If, however, the door 22 was left open for a sufiicient length of time the switch 96 would function, as stated, to close the return air dampers 94 and cause fresh air to be admitted through the dampers 36.

100 indicates a thermostat located at the door 22 and in circuit with motor 102, motor speed controller 104 and the variable speed motor 106 to the pressure blower 46.

108 indicates a damper control in the pressurized air duct 50 which, when opened, enables friction to air flow by the heater tubes 110 to be overcome when, as in summer, heat from the generator 48 is not required.

In Fig. 11 there is clearly shown the effect of the nozzles 56, 56 in directing the pressurized air, target-wise, as indicated by the arrows A and A against the entrances 16 and 22. These nozzles, therefore, are properly designed to target the air streams against said entrances.

Having thus described my invention what I claim as new and wish to protect by Letters Patent is as follows:

1. In an air conditioning system, the combination with a building space having an entrance with adjustable closure means, of air pressurizing blower means having an inlet connection to the atmosphere outside of said building space, duct means connected between said air pressurizing means and said building space to conduct high velocity air toward said entrance, said building space including return air flow means, and a pair of separate control means each operatively connected with said pressurizing means and said return air flow means, respectively, to control the pressurization of said building space in compensating relation to the tendency for air infiltration at said entrance, at least one of said control means being actuatable by the adjustment of said closure means.

2. In an air conditioning system for a building space having an entrance and adjustable closure means therefor, the combination of air pressurizing and circulating means, duct means associated with said first means including a fresh air inlet and a return for conducting pressurized air to and from said space, fresh air and return damper means in said inlet and return, switch means located adjacent said entrance in said space, means interconnecting said switch means with said fresh air and said return air damper means to control the opening and closing thereof under the influence of air infiltration through said entrance regulated by said adjustable closure means, and means for discharging air into the space at high velocity and toward such entrance.

3. In an air conditioning system, the combination with a building space having an entrance, with door closure means therefor, of air pressurizing blower means having a first air inlet duct opening into the interior of said space and a second air inlet duct opening to the outside atmosphere, a fresh air inlet damper in said second duct, a return air damper in said first duct, motor means for actuating said dampers, said fresh air inlet damper controlling the volume of fresh air admitted to said pressurization means, switch means at said entrance area connected in circuit with said motor means and said door closure means to control the actuation of said motors consequent upon the opening and closing of said door closure means, and for discharging air into the space at high velocity and toward such entrance.

References Cited in the file of this patent UNITED STATES PATENTS 843,909 Peters et a1 Feb. 12, 1907 1,832,508 Scott Nov. 17, 1931 1,981,164 Carrier Nov. 20, 1934 1,985,050 Merle Dec. 18, 1934 2,004,927 Bulkeley June 18, 1935 2,150,252 Shure Mar. 14, 1939 2,223,287 Kingsland Nov. 26, 1940 2,234,633 Hoppe Mar. 11, 1941 2,332,091 Kuhn Oct. 19, 1943 

